Barcodes and radio frequency identification (RFID) tags are examples of data tags that are widely used to mark, inventory and track various products.
Barcodes are optical, machine readable representations of data. Barcodes may be linear or two-dimensional, and can be used to store any type of data. Barcodes are commonly used to store a product identifier, but modern barcodes may include reference to a Uniform Resource Locator (URL) or other data.
RFID tags generally transmit to a reader device a radio frequency (RF) signal that includes product information. RFID tags generally include an integrated circuit for storing and processing information, a transceiver for transmitting and receiving RF signals, and an antenna. Some RFID tags are active RFID tags and include their own battery power source. Passive RFID tags do not have their own power source and require receiving a power signal from the reader device to operate. To interrogate a passive RFID tag, a reader generally transmits a continuous wave (CW) or modulated RF signal to the tag. The tag receives the signal and responds by modulating the signal and then “backscattering” an information response signal to the reader device. The reader device receives the response signal from the tag, and the response signal is demodulated, decoded and further processed.
Handheld data tag reader devices are now commonly used for identifying, cataloging, and locating various types of objects that are tagged with data tags. Such objects include relatively large products such as pallets, boxes, containers and big parts or components; and relatively small products such as fasteners, electronic components, and small parts that are stored in bins with large numbers of similar parts.
However, it is difficult to identify a location of a data tag relative to a known point when the reader device does not have a fixed position.
Accordingly, there is a need for an improved method and apparatus for identifying a location of a data tag.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.